# 去除字符串两头空格
phone = " 13800000001   "
print(phone)
print(phone.strip())

# 大小写转换
# 转大写：字符串.upper()
# 转小写：字符串.lower()

sql = "SelECt * from students where id = 001;"

print(sql.upper())
print(sql.lower())

# 查询select是否存在
if "select" in sql.upper():
    print("查询")
else:
    print("非查询")